Monday, February 20, 2006

Smart watch - directional guidance

One of the principal features of the watch is its ability to guide the user around the environment using tactile responses rather than slow and cumbersome voice prompts (although this will still be an option through the connected headset).

Talking with Mike Sharkey, our resident visual impairment expert, we discovered that any tactile guidance system must be discrete and easy to ignore if the user desires more control. Also, as per earlier posts, we won't be able to deal with object avoidance or other primary guidance due to being unable to determine features such as the slope or texture of the ground. These functions will still be left entirely in the user's control with their cane or guide dog.

Instead we will concentrate solely on 2D directional guidance for the user around a complex environment such as a supermarket's aisles.

The back face of the watch will have a ring of pressure pins, so that the strap of the watch holds them against the user's skin. If the brain of the system, using GPS location, has decided that the user needs to turn in a certain direction then different pins around the ring will activate to put a slight pressure on the user's wrist and inform them of the direction to turn in. The pins can be analagous to the points and subdivisions of a magnetic compass.

So if the user needs to make a 90 degree turn left then the three pins around the W end of the ring will activate (three pins are used to give greater width of the area of skin activated otherwise the user may miss instructions). As the user turns left, the activated pins move around the ring until the three around N are activated. At this point the user is facing in the right direction and the pins will deactivate (so as not to numb the skin through overuse). If the user strays off course, more pins are activated until they are facing in the right direction again.

Of course all of this functionality must be able to be turned off easily by the user. The ability to do this will come in a later post.


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